Imidazole and triazole carboxylates, and processes for preparing 2,4-oxazolidinediones

Abstract

Processes are described for preparing 2,4-oxazolidinediones having Formula (I) ##STR1## wherein: R 1 is phenyl optionally substituted with 1-2 halogens; or 4-phenoxy, 4-(1-phenethyloxy) or 4-benzyloxy each optionally substituted with R 2 on the phenyl ring; and R 2 is halogen; methyl; or ethyl. 2-Hydroxycarboxylic acid esters are reacted with a carbonylating agent in the presence of a base to give intermediate triazole or imidazole carboxylates. The carboxylates react with phenyl hydrazine in the presence of an acid to give the compounds of Formula (I).

What is claimed is: 
     
       1. A process for the preparation of 2.4-oxazolidinediones of Formula I ##STR10## wherein: R 1  is phenyl substituted with 1-2 halogen or R 1  is phenyl substituted with 4-phenoxy, 4-(1-phenethyloxy) or 4-benzyloxy with each 4-phenoxy, 4-(1-phenethyloxy) or 4-benzyloxy optionally substituted with R 2  on the phenyl ring; and R 2  is halogen; methyl; or ethyl; comprising 1) reacting a 2-hydroxycarboxylic acid ester of Formula II ##STR11## wherein R 1  and R 2  are defined as above for Formula I; and     R 3  is C 1  -C 4  alkyl; with a base and a carbonylating agent of Formula III ##STR12## wherein Y is 1-imidazole or 1,2,4-triazolyl, provided that Y is 1,2,4-triazolyl when R 1  in Formula II is phenyl substituted with 4-(1-phenethyloxy) or 4-benzyloxy with each 4-(1-phenethyloxy) or 4-benzyloxy optionally substituted with R 2  on the phenyl ring; to yield an intermediate compound of Formula IV: ##STR13## wherein R 1 , R 2 , R 3  and Y are defined as above: and   2) reacting a compound of Formula IV as defined above with phenylhydrazine in the presence of an acid to yield a compound of Formula I.     
     
     
       2. A process according to claim 1 wherein R 1  of Formula II is 4-phenoxyphenyl or 2,4-difluorophenyl. 
     
     
       3. A process according to claim 1 wherein R 1  of product Formula I is 4-phenoxyphenyl. 
     
     
       4. A process according to claim 1 further comprising preparing in situ the carbonylating agent of Formula III by reacting 1) phosgene, 2) one of imidazole or 1,2,4-triazole and 3) an organic base selected from the group consisting of trialkylamine, pyridine, picoline or other substituted pyridine, or by reacting 1) phosgene and 2) an alkali metal salt of 1,2,4-triazole. 
     
     
       5. A process according to claim 4 wherein the carbonylating agent of Formula III is prepared in situ by the reaction of phosgene and an alkali metal salt of 1,2,4-triazole. 
     
     
       6. A process according to claim 1 wherein the compound of Formula IV is prepared using at least one picoline as the organic base. 
     
     
       7. A process according the claim 6 wherein the reaction mixture of step 1) is filtered prior to step 2). 
     
     
       8. A process according to claim 7 wherein the acid employed in step 2) is acetic acid. 
     
     
       9. A compound of Formula IV ##STR14## wherein R 1  is phenyl substituted with 1-2 halogen; or 4-phenoxy, R 1  is phenyl substituted with 4-(1-phenethyloxy) or 4-benzyloxy each optionally substituted with R 2  on the phenyl ring; R 2  is halogen, methyl or ethyl:   R 3  is C 1  -C 4  alkyl; and   Y is 1-imidazolyl or 1,2,4-triazolyl provided that Y is 1,2,4-triazolyl when R 1  is phenyl substituted with 4-(1-phenethyloxy) or 4-benzyloxy with each 4-(1-phenethyloxy) or 4-benzyloxy optionally substituted with R 2  on the phenyl ring.   
     
     
       10. A compound of claim 9 wherein R 1  is 4-phenoxyphenyl and Y is 1,2,4-triazolyl.